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1.
Artigo em Inglês | MEDLINE | ID: mdl-31445098

RESUMO

BACKGROUND: Although chiefly a B-lymphocyte disorder, several research groups have identified common variable immunodeficiency (CVID) subjects with numerical and/or functional T helper cell alterations. The causes, interrelationships and consequences of CVID-associated CD4+ T-cell derangements to hypogammaglobulinemia and/or autoantibody production remain unclear. OBJECTIVE: To determine how circulating CD4+ T-cells are altered in CVID subjects with autoimmune cytopenias (CVID+AIC) and the causes of these derrangements. METHODS: Using hypothesis-generating, high-dimensional single-cell analyses, we created comprehensive phenotypic maps of circulating CD4+ T cells. Differences between subject groups were confirmed in a large, genetically diverse CVID subject cohort (n=69) using flow cytometry, transcriptional profiling, multiplex cytokine/chemokine detection and a suite of in vitro functional assays measuring naive T cell differentiation, B cell/T cell co-cultures and Treg suppression. RESULTS: Whereas CD4+ T helper cell profiles from healthy donors and CVID subjects without autoimmune cytopenias were virtually indistinguishable, CVID+AIC T cells exhibited follicular features as early as thymic egress. Follicular skewing correlated with IgA deficiency-associated endotoxemia and endotoxin-induced expression of activin A and ICOSL. The resulting enlarged CVID+AIC circulating Tfh (cTfh) cell population provided efficient help to receptive HD B cells but not unresponsive CVID B cells. Despite this, CVID+AIC cTfh exhibited aberrant transcriptional profiles and altered chemokine/cytokine receptor expression patterns that interfered with Treg suppression assays and were associated with autoantibody production. CONCLUSIONS: Endotoxemia is associated with early commitment to the follicular T cell lineage in IgA-deficient CVID subjects, particularly those with AICs.

2.
Front Immunol ; 9: 1715, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30087679

RESUMO

Located contiguously on the long arm of the second chromosome are gene paralogs encoding the immunoglobulin-family co-activation receptors CD28 and cytotoxic T-lymphocyte-associated protein 4 (CTLA4). CD28 and CTLA4 share the same B7 ligands yet each provides opposing proliferative signals to T cells. Herein, we describe for the first time two unrelated subjects with coexisting CD28 and CTLA4 haploinsufficiency due to heterozygous microdeletions of chromosome 2q. Although their clinical phenotype, multi-organ inflammatory disease, is superficially similar to that of CTLA4 haploinsufficient autoimmune lymphoproliferative syndrome type V (ALPS5) patients, we demonstrate our subjects' underlying immunopathology to be distinct. Unlike ALPS5 T cells which hyperproliferate to T-cell receptor-mediated activation and infiltrate organs, T cells from our subjects are hypoproliferative and do not. Instead of T cell infiltrates, biopsies of affected subject tissues demonstrated infiltrates of lineage negative lymphoid cells. This histologic feature correlated with significant increases in circulating type 3 innate lymphoid cells (ILC3s) and ILC3 cytokines, interleukin 22, and interleukin-17A. CTLA4-Ig monotherapy, which we trialed in one subject, was remarkably effective in controlling inflammatory diseases, normalizing ILC3 frequencies, and reducing ILC3 cytokine concentrations.

3.
Artigo em Inglês | MEDLINE | ID: mdl-29935219

RESUMO

BACKGROUND: The lack of pathogen-protective, isotype-switched antibodies in patients with common variable immunodeficiency (CVID) suggests germinal center (GC) hypoplasia, yet a subset of patients with CVID is paradoxically affected by autoantibody-mediated autoimmune cytopenias (AICs) and lymphadenopathy. OBJECTIVE: We sought to compare the physical characteristics and immunologic output of GC responses in patients with CVID with AIC (CVID+AIC) and without AIC (CVID-AIC). METHODS: We analyzed GC size and shape in excisional lymph node biopsy specimens from 14 patients with CVID+AIC and 4 patients with CVID-AIC. Using paired peripheral blood samples, we determined how AICs specifically affected B-and T-cell compartments and antibody responses in patients with CVID. RESULTS: We found that patients with CVID+AIC displayed irregularly shaped hyperplastic GCs, whereas GCs were scarce and small in patients with CVID-AIC. GC hyperplasia was also evidenced by an increase in numbers of circulating follicular helper T cells, which correlated with decreased regulatory T-cell frequencies and function. In addition, patients with CVID+AIC had serum endotoxemia associated with a dearth of isotype-switched memory B cells that displayed significantly lower somatic hypermutation frequencies than their counterparts with CVID-AIC. Moreover, IgG+ B cells from patients with CVID+AIC expressed VH4-34-encoded antibodies with unmutated Ala-Val-Tyr and Asn-His-Ser motifs, which recognize both erythrocyte I/i self-antigens and commensal bacteria. CONCLUSIONS: Patients with CVID+AIC do not contain mucosal microbiota and exhibit hyperplastic yet inefficient GC responses that favor the production of untolerized IgG+ B-cell clones that recognize both commensal bacteria and hematopoietic I/i self-antigens.

5.
J Allergy Clin Immunol Pract ; 5(5): 1344-1350.e3, 2017 Sep - Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28286158

RESUMO

BACKGROUND: Smith-Magenis syndrome (SMS) is a complex neurobehavioral disorder associated with recurrent otitis. Most SMS cases result from heterozygous interstitial chromosome 17p11.2 deletions that encompass not only the intellectual disability gene retinoic acid-induced 1 but also other genes associated with immunodeficiency, autoimmunity, and/or malignancy. OBJECTIVES: The goals of this study were to describe the immunological consequence of 17p11.2 deletions by determining the prevalence of immunological diseases in subjects with SMS and by assessing their immune systems via laboratory methods. METHODS: We assessed clinical histories of 76 subjects with SMS with heterozygous 17p11.2 deletions and performed in-depth immunological testing on 25 representative cohort members. Laboratory testing included determination of serum antibody concentrations, vaccine titers, and lymphocyte subset frequencies. Detailed reactivity profiles of SMS serum antibodies were performed using custom-made antigen microarrays. RESULTS: Of 76 subjects with SMS, 74 reported recurrent infections including otitis (88%), pneumonia (47%), sinusitis (42%), and gastroenteritis (34%). Infections were associated with worsening SMS-related neurobehavioral symptoms. The prevalence of autoimmune and atopic diseases was not increased. Malignancy was not reported. Laboratory evaluation revealed most subjects with SMS to be deficient of isotype-switched memory B cells and many to lack protective antipneumococcal antibodies. SMS antibodies were not more reactive than control antibodies to self-antigens. CONCLUSIONS: Patients with SMS with heterozygous 17p.11.2 deletions display an increased susceptibility to sinopulmonary infections, but not to autoimmune, allergic, or malignant diseases. SMS sera display an antibody reactivity profile favoring neither recognition of pathogen-associated antigens nor self-antigens. Prophylactic strategies to prevent infections may also provide neurobehavioral benefits to selected patients with SMS.


Assuntos
Linfócitos B/imunologia , Síndromes de Imunodeficiência/epidemiologia , Síndrome de Smith-Magenis/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Estudos de Coortes , Proteína DEAD-box 58/genética , Feminino , Humanos , Switching de Imunoglobulina , Memória Imunológica , Lactente , Deficiência Intelectual , Masculino , Mutação/genética , Otite , Pneumonia , Prevalência , Sinusite , Síndrome de Smith-Magenis/genética , Síndrome de Smith-Magenis/imunologia , Adulto Jovem
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